Providing good quality radio coverage in a mobile or cellular telecommunications network using a macro network is very expensive due to the short range of the signals from base stations.
Many geographical areas covered by radio networks experience poor network coverage due to the local terrain or buildings.
Additionally, indoor users can experience particularly poor coverage due to the penetration losses of the radio signals through walls. Analysis shows that up to 70% of mobile terminal users are located indoors. A high percentage of these users suffer from poor coverage which will impact mobile terminal battery life, user throughput and network performance and efficiency. Providing indoor coverage of UMTS is particularly difficult due to the high frequency, and, hence, high penetration losses, of the UMTS signals.
It is desirable to improve the quality of the coverage throughout the coverage areas and, in particular, to boost the power of the network signals in order that the signals can penetrate into buildings.
One solution to improving the coverage and local power of the signals is to increase the density of the deployed (macro) base stations. However, this is a very expensive solution.
An alternative solution for improving coverage is to boost the signal locally using dedicated repeaters. Typically, repeaters act as simple amplifiers to amplify and transmit all signals that they receive. Repeaters transmit all signals and so will amplify both uplink and downlink signals.
Although repeaters can help to provide network coverage in areas not covered by the macro network and boost the power of signals, the use of repeaters cause particular problems in the uplink direction. Since a large portion of the signals received by a repeater are noise, for example downlink signals or general background radio signals from distant cells or devices, a large part of the network capacity in the uplink is wasted as it is occupied by signals amplified by the repeater and which are not useful to the network in the uplink.